With known materials, cards can be manufactured for many requirements. Nevertheless, there is a fundamental desire to continually increase the spectrum of possible card constructions, in order to accordingly increase the spectrum of satisfiable requirements.
From EP 945244 A1 there is known a method for manufacturing a synthetic paper which is especially environmentally friendly. The manufactured synthetic paper consists, based on weight, of 56% to 80% inorganic grit, in particular calcium carbonate, and contains, based on weight, a content of 18% to 43% polyethylene, in particular high-density polyethylene.
From U.S. Pat. No. 4,879,153 A there is known an IC card constructed from a plurality of laminated layers, which has a core structure consisting of a plurality of rigid PVC layers with a cavity in which an IC module is disposed. For improving the bending strength of the card, layers of synthetic paper are furthermore formed on one or both sides of the core structure. The total thickness thereof preferably amounts to up to one third of the total card thickness. At least one of the layers of synthetic paper is so disposed that it lies against the underside of the IC module. The known solution is restricted to utilizing the bending-elastic properties of synthetic paper. Since the proposed card consists for the greater part of PVC, it is to be assessed rather critically with regard to its environmental compatibility from today's point of view.